Humidity control systems, configured to provide indoor humidity control by adsorption-desorption of moisture present in the air, have been known in the art for many years.
For example, Japanese patent document No. JP-A-2004-294048 discloses a humidity control system including a refrigerant circuit to which an adsorption heat exchanger is connected. Also connected to the refrigerant circuit of the humidity control system are a compressor, a first adsorption heat exchanger, an expansion valve, a second adsorption heat exchanger, and a four-way valve. The refrigerant is circulated through the refrigerant circuit whereby the refrigeration cycle is performed. As a result, one of the two adsorption heat exchangers functions as an evaporator while the other of the two adsorption heat exchangers functions as a condenser.
More specifically, when the humidity control system is operating in the humidification mode, outdoor air is passed through an adsorption heat exchanger serving as a condenser. In the adsorption heat exchanger (condenser), its adsorbent is heated by refrigerant, and moisture is desorbed from the adsorbent. The desorbed moisture is discharged to the outdoor air. The air thus humidified is supplied to the room whereby indoor humidification is provided. Meanwhile, indoor air is passed through an adsorption heat exchanger serving as an evaporator. In the adsorption heat exchanger (evaporator), its adsorbent is cooled by refrigerant and at the same time that moisture present in the air is adsorbed on the adsorbent, the resulting heat of adsorption is removed to the refrigerant. The air whose moisture content has been thus imparted to the adsorbent is discharged to outside the room.
On the other hand, when the humidity control system is operating in the dehumidification mode, outdoor air is passed through an adsorption heat exchanger serving as an evaporator. In the adsorption heat exchanger (evaporator), its adsorbent is cooled by refrigerant and at the same time that moisture present in the air is adsorbed on the adsorbent, the resulting heat of adsorption is removed to the refrigerant. The air thus dehumidified is supplied to the room whereby indoor dehumidification is provided. Meanwhile, indoor air is passed through an adsorption heat exchanger serving as a condenser. In the adsorption heat exchanger (condenser), its adsorbent is heated by refrigerant and moisture is desorbed from the adsorbent. The desorbed moisture is discharged to the air. The air which has been thus used to regenerate the adsorbent is discharged to outside the room.
In the humidity control system, the circulation direction of the refrigerant in the refrigerant circuit is switched by the four-way valve simultaneously with switching the flow path of air by means of a damper whereby the operation of regeneration and the operation of adsorption are alternately repeatedly performed in the two adsorption heat exchangers. That is to say, the humidity control system provides continuous supply of humidity-controlled air to the room without impairing both the capability of adsorption and the capability of being regenerated of the adsorbents.
These adsorption heat exchangers used for air humidity control are each made up of a heat exchanger main body and an adsorbent laminated film (adsorption layer) formed on the heat exchanger main body. The heat exchanger main body is implemented by a fin and tube heat exchanger which is made up of a large number of fins of aluminum which are formed in rectangular shapes and arranged in parallel with each other, and a heat transfer tube of copper which is passed through each of the fins. Also note that zeolite, silica gel, activated carbon, or any other suitable substance in powder form may be used as an adsorbent for the adsorption heat exchangers.